1//===----- CGCall.h - Encapsulate calling convention details ----*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// These classes wrap the information about a call or function
10// definition used to handle ABI compliancy.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_LIB_CODEGEN_CGCALL_H
15#define LLVM_CLANG_LIB_CODEGEN_CGCALL_H
16
17#include "CGValue.h"
18#include "EHScopeStack.h"
19#include "clang/AST/ASTFwd.h"
20#include "clang/AST/CanonicalType.h"
21#include "clang/AST/GlobalDecl.h"
22#include "clang/AST/Type.h"
23#include "llvm/IR/Value.h"
24
25namespace llvm {
26class Type;
27class Value;
28} // namespace llvm
29
30namespace clang {
31class Decl;
32class FunctionDecl;
33class TargetOptions;
34class VarDecl;
35
36namespace CodeGen {
37
38/// Abstract information about a function or function prototype.
39class CGCalleeInfo {
40 /// The function prototype of the callee.
41 const FunctionProtoType *CalleeProtoTy;
42 /// The function declaration of the callee.
43 GlobalDecl CalleeDecl;
44
45public:
46 explicit CGCalleeInfo() : CalleeProtoTy(nullptr) {}
47 CGCalleeInfo(const FunctionProtoType *calleeProtoTy, GlobalDecl calleeDecl)
48 : CalleeProtoTy(calleeProtoTy), CalleeDecl(calleeDecl) {}
49 CGCalleeInfo(const FunctionProtoType *calleeProtoTy)
50 : CalleeProtoTy(calleeProtoTy) {}
51 CGCalleeInfo(GlobalDecl calleeDecl)
52 : CalleeProtoTy(nullptr), CalleeDecl(calleeDecl) {}
53
54 const FunctionProtoType *getCalleeFunctionProtoType() const {
55 return CalleeProtoTy;
56 }
57 const GlobalDecl getCalleeDecl() const { return CalleeDecl; }
58};
59
60/// All available information about a concrete callee.
61class CGCallee {
62 enum class SpecialKind : uintptr_t {
63 Invalid,
64 Builtin,
65 PseudoDestructor,
66 Virtual,
67
68 Last = Virtual
69 };
70
71 struct BuiltinInfoStorage {
72 const FunctionDecl *Decl;
73 unsigned ID;
74 };
75 struct PseudoDestructorInfoStorage {
76 const CXXPseudoDestructorExpr *Expr;
77 };
78 struct VirtualInfoStorage {
79 const CallExpr *CE;
80 GlobalDecl MD;
81 Address Addr;
82 llvm::FunctionType *FTy;
83 };
84
85 SpecialKind KindOrFunctionPointer;
86 union {
87 CGCalleeInfo AbstractInfo;
88 BuiltinInfoStorage BuiltinInfo;
89 PseudoDestructorInfoStorage PseudoDestructorInfo;
90 VirtualInfoStorage VirtualInfo;
91 };
92
93 explicit CGCallee(SpecialKind kind) : KindOrFunctionPointer(kind) {}
94
95 CGCallee(const FunctionDecl *builtinDecl, unsigned builtinID)
96 : KindOrFunctionPointer(SpecialKind::Builtin) {
97 BuiltinInfo.Decl = builtinDecl;
98 BuiltinInfo.ID = builtinID;
99 }
100
101public:
102 CGCallee() : KindOrFunctionPointer(SpecialKind::Invalid) {}
103
104 /// Construct a callee. Call this constructor directly when this
105 /// isn't a direct call.
106 CGCallee(const CGCalleeInfo &abstractInfo, llvm::Value *functionPtr)
107 : KindOrFunctionPointer(
108 SpecialKind(reinterpret_cast<uintptr_t>(functionPtr))) {
109 AbstractInfo = abstractInfo;
110 assert(functionPtr && "configuring callee without function pointer");
111 assert(functionPtr->getType()->isPointerTy());
112 }
113
114 static CGCallee forBuiltin(unsigned builtinID,
115 const FunctionDecl *builtinDecl) {
116 CGCallee result(SpecialKind::Builtin);
117 result.BuiltinInfo.Decl = builtinDecl;
118 result.BuiltinInfo.ID = builtinID;
119 return result;
120 }
121
122 static CGCallee forPseudoDestructor(const CXXPseudoDestructorExpr *E) {
123 CGCallee result(SpecialKind::PseudoDestructor);
124 result.PseudoDestructorInfo.Expr = E;
125 return result;
126 }
127
128 static CGCallee forDirect(llvm::Constant *functionPtr,
129 const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
130 return CGCallee(abstractInfo, functionPtr);
131 }
132
133 static CGCallee forDirect(llvm::FunctionCallee functionPtr,
134 const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
135 return CGCallee(abstractInfo, functionPtr.getCallee());
136 }
137
138 static CGCallee forVirtual(const CallExpr *CE, GlobalDecl MD, Address Addr,
139 llvm::FunctionType *FTy) {
140 CGCallee result(SpecialKind::Virtual);
141 result.VirtualInfo.CE = CE;
142 result.VirtualInfo.MD = MD;
143 result.VirtualInfo.Addr = Addr;
144 result.VirtualInfo.FTy = FTy;
145 return result;
146 }
147
148 bool isBuiltin() const {
149 return KindOrFunctionPointer == SpecialKind::Builtin;
150 }
151 const FunctionDecl *getBuiltinDecl() const {
152 assert(isBuiltin());
153 return BuiltinInfo.Decl;
154 }
155 unsigned getBuiltinID() const {
156 assert(isBuiltin());
157 return BuiltinInfo.ID;
158 }
159
160 bool isPseudoDestructor() const {
161 return KindOrFunctionPointer == SpecialKind::PseudoDestructor;
162 }
163 const CXXPseudoDestructorExpr *getPseudoDestructorExpr() const {
164 assert(isPseudoDestructor());
165 return PseudoDestructorInfo.Expr;
166 }
167
168 bool isOrdinary() const {
169 return uintptr_t(KindOrFunctionPointer) > uintptr_t(SpecialKind::Last);
170 }
171 CGCalleeInfo getAbstractInfo() const {
172 if (isVirtual())
173 return VirtualInfo.MD;
174 assert(isOrdinary());
175 return AbstractInfo;
176 }
177 llvm::Value *getFunctionPointer() const {
178 assert(isOrdinary());
179 return reinterpret_cast<llvm::Value *>(uintptr_t(KindOrFunctionPointer));
180 }
181 void setFunctionPointer(llvm::Value *functionPtr) {
182 assert(isOrdinary());
183 KindOrFunctionPointer =
184 SpecialKind(reinterpret_cast<uintptr_t>(functionPtr));
185 }
186
187 bool isVirtual() const {
188 return KindOrFunctionPointer == SpecialKind::Virtual;
189 }
190 const CallExpr *getVirtualCallExpr() const {
191 assert(isVirtual());
192 return VirtualInfo.CE;
193 }
194 GlobalDecl getVirtualMethodDecl() const {
195 assert(isVirtual());
196 return VirtualInfo.MD;
197 }
198 Address getThisAddress() const {
199 assert(isVirtual());
200 return VirtualInfo.Addr;
201 }
202 llvm::FunctionType *getVirtualFunctionType() const {
203 assert(isVirtual());
204 return VirtualInfo.FTy;
205 }
206
207 /// If this is a delayed callee computation of some sort, prepare
208 /// a concrete callee.
209 CGCallee prepareConcreteCallee(CodeGenFunction &CGF) const;
210};
211
212struct CallArg {
213private:
214 union {
215 RValue RV;
216 LValue LV; /// The argument is semantically a load from this l-value.
217 };
218 bool HasLV;
219
220 /// A data-flow flag to make sure getRValue and/or copyInto are not
221 /// called twice for duplicated IR emission.
222 mutable bool IsUsed;
223
224public:
225 QualType Ty;
226 CallArg(RValue rv, QualType ty)
227 : RV(rv), HasLV(false), IsUsed(false), Ty(ty) {}
228 CallArg(LValue lv, QualType ty)
229 : LV(lv), HasLV(true), IsUsed(false), Ty(ty) {}
230 bool hasLValue() const { return HasLV; }
231 QualType getType() const { return Ty; }
232
233 /// \returns an independent RValue. If the CallArg contains an LValue,
234 /// a temporary copy is returned.
235 RValue getRValue(CodeGenFunction &CGF) const;
236
237 LValue getKnownLValue() const {
238 assert(HasLV && !IsUsed);
239 return LV;
240 }
241 RValue getKnownRValue() const {
242 assert(!HasLV && !IsUsed);
243 return RV;
244 }
245 void setRValue(RValue _RV) {
246 assert(!HasLV);
247 RV = _RV;
248 }
249
250 bool isAggregate() const { return HasLV || RV.isAggregate(); }
251
252 void copyInto(CodeGenFunction &CGF, Address A) const;
253};
254
255/// CallArgList - Type for representing both the value and type of
256/// arguments in a call.
257class CallArgList : public SmallVector<CallArg, 8> {
258public:
259 CallArgList() : StackBase(nullptr) {}
260
261 struct Writeback {
262 /// The original argument. Note that the argument l-value
263 /// is potentially null.
264 LValue Source;
265
266 /// The temporary alloca.
267 Address Temporary;
268
269 /// A value to "use" after the writeback, or null.
270 llvm::Value *ToUse;
271 };
272
273 struct CallArgCleanup {
274 EHScopeStack::stable_iterator Cleanup;
275
276 /// The "is active" insertion point. This instruction is temporary and
277 /// will be removed after insertion.
278 llvm::Instruction *IsActiveIP;
279 };
280
281 void add(RValue rvalue, QualType type) { push_back(CallArg(rvalue, type)); }
282
283 void addUncopiedAggregate(LValue LV, QualType type) {
284 push_back(CallArg(LV, type));
285 }
286
287 /// Add all the arguments from another CallArgList to this one. After doing
288 /// this, the old CallArgList retains its list of arguments, but must not
289 /// be used to emit a call.
290 void addFrom(const CallArgList &other) {
291 insert(end(), other.begin(), other.end());
292 Writebacks.insert(Writebacks.end(), other.Writebacks.begin(),
293 other.Writebacks.end());
294 CleanupsToDeactivate.insert(CleanupsToDeactivate.end(),
295 other.CleanupsToDeactivate.begin(),
296 other.CleanupsToDeactivate.end());
297 assert(!(StackBase && other.StackBase) && "can't merge stackbases");
298 if (!StackBase)
299 StackBase = other.StackBase;
300 }
301
302 void addWriteback(LValue srcLV, Address temporary, llvm::Value *toUse) {
303 Writeback writeback = {srcLV, temporary, toUse};
304 Writebacks.push_back(writeback);
305 }
306
307 bool hasWritebacks() const { return !Writebacks.empty(); }
308
309 typedef llvm::iterator_range<SmallVectorImpl<Writeback>::const_iterator>
310 writeback_const_range;
311
312 writeback_const_range writebacks() const {
313 return writeback_const_range(Writebacks.begin(), Writebacks.end());
314 }
315
316 void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup,
317 llvm::Instruction *IsActiveIP) {
318 CallArgCleanup ArgCleanup;
319 ArgCleanup.Cleanup = Cleanup;
320 ArgCleanup.IsActiveIP = IsActiveIP;
321 CleanupsToDeactivate.push_back(ArgCleanup);
322 }
323
324 ArrayRef<CallArgCleanup> getCleanupsToDeactivate() const {
325 return CleanupsToDeactivate;
326 }
327
328 void allocateArgumentMemory(CodeGenFunction &CGF);
329 llvm::Instruction *getStackBase() const { return StackBase; }
330 void freeArgumentMemory(CodeGenFunction &CGF) const;
331
332 /// Returns if we're using an inalloca struct to pass arguments in
333 /// memory.
334 bool isUsingInAlloca() const { return StackBase; }
335
336private:
337 SmallVector<Writeback, 1> Writebacks;
338
339 /// Deactivate these cleanups immediately before making the call. This
340 /// is used to cleanup objects that are owned by the callee once the call
341 /// occurs.
342 SmallVector<CallArgCleanup, 1> CleanupsToDeactivate;
343
344 /// The stacksave call. It dominates all of the argument evaluation.
345 llvm::CallInst *StackBase;
346};
347
348/// FunctionArgList - Type for representing both the decl and type
349/// of parameters to a function. The decl must be either a
350/// ParmVarDecl or ImplicitParamDecl.
351class FunctionArgList : public SmallVector<const VarDecl *, 16> {};
352
353/// ReturnValueSlot - Contains the address where the return value of a
354/// function can be stored, and whether the address is volatile or not.
355class ReturnValueSlot {
356 Address Addr = Address::invalid();
357
358 // Return value slot flags
359 unsigned IsVolatile : 1;
360 unsigned IsUnused : 1;
361 unsigned IsExternallyDestructed : 1;
362
363public:
364 ReturnValueSlot()
365 : IsVolatile(false), IsUnused(false), IsExternallyDestructed(false) {}
366 ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused = false,
367 bool IsExternallyDestructed = false)
368 : Addr(Addr), IsVolatile(IsVolatile), IsUnused(IsUnused),
369 IsExternallyDestructed(IsExternallyDestructed) {}
370
371 bool isNull() const { return !Addr.isValid(); }
372 bool isVolatile() const { return IsVolatile; }
373 Address getValue() const { return Addr; }
374 bool isUnused() const { return IsUnused; }
375 bool isExternallyDestructed() const { return IsExternallyDestructed; }
376};
377
378/// Helper to add attributes to \p F according to the CodeGenOptions and
379/// LangOptions without requiring a CodeGenModule to be constructed.
380void mergeDefaultFunctionDefinitionAttributes(llvm::Function &F,
381 const CodeGenOptions CodeGenOpts,
382 const LangOptions &LangOpts,
383 const TargetOptions &TargetOpts,
384 bool WillInternalize);
385
386enum class FnInfoOpts {
387 None = 0,
388 IsInstanceMethod = 1 << 0,
389 IsChainCall = 1 << 1,
390 IsDelegateCall = 1 << 2,
391};
392
393inline FnInfoOpts operator|(FnInfoOpts A, FnInfoOpts B) {
394 return static_cast<FnInfoOpts>(
395 static_cast<std::underlying_type_t<FnInfoOpts>>(A) |
396 static_cast<std::underlying_type_t<FnInfoOpts>>(B));
397}
398
399inline FnInfoOpts operator&(FnInfoOpts A, FnInfoOpts B) {
400 return static_cast<FnInfoOpts>(
401 static_cast<std::underlying_type_t<FnInfoOpts>>(A) &
402 static_cast<std::underlying_type_t<FnInfoOpts>>(B));
403}
404
405inline FnInfoOpts operator|=(FnInfoOpts A, FnInfoOpts B) {
406 A = A | B;
407 return A;
408}
409
410inline FnInfoOpts operator&=(FnInfoOpts A, FnInfoOpts B) {
411 A = A & B;
412 return A;
413}
414
415} // end namespace CodeGen
416} // end namespace clang
417
418#endif
419